1. Field of Invention
An adapter attached between a syringe containing a bone void filler and the head of a cannulated surgical screw allows the cannulated surgical screw to be used as a port to inject bone void filler into a bone void during the course of a surgical repair which would use a surgical screw to attach broken or separated bone fragments providing a more secure bone anchor matrix within which the surgical screw is set.
2. Description of Prior Art
A preliminary review of prior art patents was conducted by the applicant which reveal no prior art patents in a similar field or having similar use in the field of orthopedic surgery. The disclosed prior art inventions do not disclose the same or similar elements as the present cannulated screw bone filler adapter, nor do they present the material components in a manner contemplated or anticipated in the prior art.
Bone cements are known in the art of orthopedic surgery and have been discussed in articles including The use of Calcium Phosphate Bone Cement in fracture Treatment, Bajammal, Sohail S., et al., Journal of Bone and Joint Surgery, Volume 90, pgs. 1186-1196, and articles referenced therein and in U.S. Patent Application No. 2007/0032567 to Beyar. Methods of injection of a bone filler are disclosed in U.S. Patent Application No. 2009/0054934, to Beyar, which provide methods for accessing a void in the bone, introduction of bone cement into a void, introduction of an expandable filler into the void, expanding the filler and allowing the cement to set. This application clearly points out a danger in contamination of non-intentional tissue surrounding the fracture site with the bone cement by leakage or by overfill causing further damage to the affected bone being repaired and also by introduction of the bone cement through mistake or accident. Other methods employing the use of a surgical procedure known as Kyphoplasty, wherein a balloon is inflated within a bone void with the balloon further filled with a bone filler material to minimize collateral exposure to the bone cement, is demonstrated in U.S. Patent Application No. 2006/0122625 to Truckai.
Another patent application, U.S. patent Application No 2007/0055257 to Vaccaro, has attempted to utilize modified cannulated screws to accomplish an injection of a syringe containing a bone filler, the head of the cannulated screw having an externally threaded inner head adapted to a syringe having an internally threaded collar with an injector tip which enters the longitudinal central bore in the cannulated screw, the cannulated screw having a side discharge port to release the bone filler injected into the central bore.
The present adapter utilizes a typical prior art cannulated surgical screw as shown in FIGS. 1A-1C, available from surgical supply companies including MIKROMED, DEPUY®, OSTEOMED® and SYNTHES®. The adapted secures to the head of the cannulated screw by screwing the two threaded components together, locking the adapter to the head of the cannulated screw. A pre-filled bone filler syringe having a course outer thread which would normally be adapted to receive an internally threaded head portion of a hollow needle would then be attached to an internally threaded head cap of the upper component of the adapter, after which the bone filler contained within syringe may be injected through the adapter and the longitudinal central bore of the cannulated screw through the tip of the cannulated screw into a bone void below the tip of the cannulated screw which will secure the tip of the cannulated screw into the bone void filler cement subsequent to the hardening of the cement. Anchoring the tip of the surgical screw would reduce the chance of the screw backing out of the bone, which is not an uncommon occurrence, in the same manner that filling a post hole with cement to anchor a fencepost stabilizes and supports the fencepost over simply ramming the fencepost into the dirt.